The only way to fail his classes, he'd tell students, was to break a beaker or hand him something hot. "Glass doesn't bounce," was another oft-stated maxim to his sometimes fumble-fingered charges, Markelz said.

For most of his long tenure, Mr. Smith commuted to the school in Chicago's Woodlawn neighborhood from his home on the Far Northwest Side.

"I never heard him come home one night and complain about the long day," said his wife, Madeleine.

The son of a doctor, Mr. Smith grew up in the city's South Shore neighborhood and graduated from Mt. Carmel in 1947.

He received a bachelor's degree in science from Loras College in Iowa before going to collect the transcript that inadvertently led to his long tenure at his high school alma mater.

From late spring through fall, he managed concession stands at Soldier Field and other Chicago Park District venues, a job that led to summer employment for many of his students.

A commitment to Catholic education and his students kept him at Mt. Carmel, his daughter said.

"He loved the boys. He loved seeing each of them getting a taste of success," she said.

Mr. Smith was the longtime chairman of Mt. Carmel's science department and president of the Lay Teacher Association, which pressed for better pay for teachers in private schools.

In his last couple of years at Mt. Carmel, he took a reduced schedule, teaching three classes instead of five. Poor health finally forced his retirement in 2004, after which he moved to Glenview.

"Every year at around this time, I'd say I'll bet you're glad not to be going back down there," his wife said. "And he'd say no.

"I think he would have gone back if he could have."

Mr. Smith also is survived by another daughter, Virginia Lange; and four grandchildren.

Mass will be said at 10 a.m. Wednesday in Our Lady of Perpetual Help Catholic Church, 1775 Grove St., Glenview.